a) Field of the Invention
The invention relates to a closing unit for a vacuum valve comprising a first valve plate for closing a first valve opening of the vacuum valve and a second valve plate for closing a second valve opening of the vacuum valve. The invention further relates to a vacuum valve comprising a valve housing with a first valve opening that is surrounded by a first valve seat, a second valve opening that is surrounded by a second valve seat, and a closing unit that has a first valve plate for closing the first valve opening and a second valve plate for closing the second valve opening. The invention further relates to a valve plate for attaching to a carrier plate of a closing unit for a vacuum valve.
b) Description of Related Prior Art
A vacuum valve that has a valve housing with first and second valve openings that can be alternatively closed by means of first and second valve plates is known from U.S. Pat. No. 6,390,448 B1 and U.S. Pat. No. 6,913,243 B1. The two valve plates are held on a valve rod or an end piece attached to the valve rod, wherein the attachment is realized by a swivel pin, so that the angular position of a corresponding valve plate is adjustable relative to the valve rod. In the opened state of the vacuum valve, the valve rod is retracted and the two valve openings are released. For closing the vacuum valve, the two valve plates are moved initially starting from the open position into an intermediate position in which they lie between the two valve openings, wherein they are lifted from the valve openings. Starting from this intermediate position, by pivoting the valve rod about a pivoting axis at a right angle to the valve rod, either the first valve opening is closed by the first valve plate or the second valve opening is closed by the second valve plate. For example, in the closed state of the first valve opening, the second valve plate could be serviced, e.g., for exchanging the seal, and vice versa.
From U.S. Pat. No. 6,095,741, a vacuum valve with first and second valve openings is further known that can be closed by first and second valve plates, wherein each of the valve plates is connected to a separate valve rod.
A vacuum valve with first and second valve plates that are adjustable independent of each other emerges from WO 2009/070824 A1. One of the valve plates is carried by a carrier unit that is attached to valve rods. The carrier unit is equipped with several actuators for adjusting the valve plate and the valve plate is connected to these actuators by means of guides that are constructed like a kind of dovetailed guide, so that the valve plate can be removed from the actuators.
A holder of a valve plate on a valve rod in which the valve plate can be pivoted to a limited extent about the axis of the valve plate, in order to adapt the position of the valve plate to the valve seat, emerges from U.S. Pat. No. 7,134,642 B2.
From U.S. Pat. No. 6,471,181 B2, a holder of a valve plate on a valve rod is known in which the valve plate can be tilted about an axis that is at a right angle to the axis of the valve rod.